Chuck's House of VAX

Last Update: 21-Oct-2001

Welcome to my VAX pages! I accidentally got
into VAX collecting when I bought two at a sealed bid auction for
$26. One was in a DEC BA123 cabinet and the other was in a third-party BA123-like cabinet (Sigma Information Systems).
Because I had this old computer, and I'm fond of old computers, I
decided to find out what I could about it (lots) and then
discovered that they are a lot of fun to play with.

NetBSD Resources

I'm a big fan of NetBSD running on these VAXen. As I
develop things for them I will put links to them here. Currently I've got two
interesting links: [Sorry these are out of date, I'll update
them when I get 1.5.2 running on my VAXen soon! -- Chuck]

netbsd.mv2.gz
-- This is a 1.5 kernel build with just KA630/KA650 support for small
memory systems.

MVII
-- This is the configuration file I used to configure the above kernel.

Some VAX History

VAX stands for Virtual Address
eXtension, and it is basically the PDP-11
architecture (16 bits) extended to 32 bits with support for paged
virtual memory and twice as many registers. It was introduced in 1977 in
the form of the VAX 11/780. With a clock rate that allowed it to
execute one million instructions per second, and a price point
that allowed many universities and other institutions to buy one,
its popularity and accessibility helped the VAX become the
"gold standard" to measure against. Based on what a VAX
could do, The first "chip" version of the VAX architecture was the
MicroVAX 1. It was only 1/3 the performance of the 11/780 and only slightly
faster than the 11/23. Its CPU Module ID is KD32, that would make it a PDP-11
CPU which were generally KDx11 modules. It used the same bus as the PDP-11
(called the LSI-11 bus) but that was later rechristened the Q-Bus. With
the introduction of the
MicroVAX II in 1985 at 90% the speed of an 11/780 the age of the Q-Bus based
VAX officially began in earnest.

Carnegie-Mellon University described the
"ideal" computer in a paper describing the future
computing environment of choice [does anyone have the exact title? I've not
found it yet --Chuck]:

One Million Instructions Per Second;

One Million Words of memory;

One Million Pixels of screen
real-estate.

This became known as the "3M"
machine specification and was the definition of a
"workstation" for a long time. Of course the use of a
Digital Equipment Corporation machine as the standard by which to
measure performance was met with not a little bit of controversy
in the computer world.

The center of the controversy was that the
term "MIPS" with originally stood for "Millions of
Instructions Per Second" became more commonly known as the
"Meaningless Indicator of Processor Speed." [I credit this re-interpretation to
John Mashey who authored some very good analysis of instruction architecture.
--Chuck] The controversy
centered around the difficulty of comparing dissimilar
architectures using something as mundane as the number of
instructions it could crank through in one second. In particular,
the RISC chips that were introduced in the mid-80's could claim
"10 MIPS" but that did not mean they got 10x the number
of things done as a VAX! .

However, a couple of things that happened
that certainly affected my life were that DARPA (the Defense
Advanced Research Projects Agency) contracted with the Computer
Sciences Research Group to port a version of a (at the time) new
and experimental operating system called UNIX to the VAX
architecture. As I understand it CSRG had already ported a
version of their UNIX to the PDP-11 and it was logically just an
extension of that work to make it run on a VAX. Further, it gave
DARPA access to an operating system that was "free" and
unencumbered, which VMS most certainly was not.

My first encounter with this OS was in
college when my wife-to-be was working on a project to port it to
a Data General Eclipse machine, but my first meaningful encounter
was when I went to work at Sun Microsystems in the mid-80's. I
joined Sun after proposing that Intel should build a system that
would later be called a "Workstation" out of the 80386
and a graphics chip I had been working on. Intel wasn't convinced
that there was much of a market for workstations beyond MCAD and
ECAD type design engineers and while they were aggressively (for
them anyway, in a chip recession no less) pursuing being in the
"systems" business, they were ignoring this segment. I
on the other hand had a wife who was working at Xerox in Palo
Alto and she was using a "Dandelion" and
"XDE" to do code development and it was waaay cooler
than 80 x 24 terminals any day. Of course Xerox (corporate)
didn't have a clue about workstations either, but Sun did. I
joined in 1986 and never looked back.

"So How Come You Got One?"

Good question! Well as I mentioned when I
started, I ended up with two MicroVAX II systems for $26. The
MicroVAX II was in fact DEC's response to the CMU "3-M"
machine spec, and with a graphics interface you could nearly
build a 3M machine (0.9 MIPS, 1MW (4 Mb) memory, and ~1MPixel
(1024x768)). [ Sun on
the other hand had a display that was 1152 x 864 which came much
closer to actually being 1Mpixel --Chuck]

And while I worked at Sun, DEC was one of
the "bad guys". However, I had a good friend who worked
at DEC and had paid a good chunk of my college tuition by
programming an 11/55 and a variety of KL-10s (USC-ECL) The lynch
pin was that the NetBSD
Project had started an effort to
port NetBSD to the VAX (how's that for coming full circle!) and I
thought it would be fun to help out that effort in my spare time.